Covid-19 antibodies found in 16% people of Karnataka: Minister K Sudhakar

A serosurvey has revealed that around 16 per cent of the people in Karnataka have developed antibodies against Covid-19 virus, said Health and Medical Education Minister Dr K Sudhakar.

He was speaking in a press conference held in Vidhana Soudha on Wednesday.

According to a statement from Karnataka's Health Ministry, the Minister said, "A survey to estimate the prevalence of COVID-19 in Karnataka was done from September 3-16, 2020. This included the proportion of people who had COVID-19 infection recently and those currently having active SARS-CoV-2 infection. The sampled population surveyed were all adults aged 18 years and above. All 30 districts of the state, including eight zones of BBMP, were included in the survey. The survey was conducted in hospitals and selected population settings."

The Minister said that three groups of the population were covered that included low-risk group, i.e., pregnant women attending the antenatal clinic, persons attending the outpatient department in the hospitals/attendees of children or patients; moderate-risk group, i.e., persons moving in the community like bus conductors, vendors at the vegetable markets, health care workers, individuals in containment zones and congregate settings such as markets, malls, retail stores, bus stops, railway stations, pourakarmikas/ waste collectors; and high-risk group.i.e. elderly and persons with comorbid conditions.

The study used Rapid Antigen Test (RAT) and RT-PCR for the diagnosis of acute infection. At the same time, serum testing for IgG antibodies was conducted to know the protection offered by the immune response. The standard ICMR protocols were used, and ICMR approved laboratory network in the state was utilised, Dr Sudhakar added.

Of the 16,585 persons surveyed covering the three risk categories, the analysis was done on results for 15,624 individuals whose RAT plus RT-PCR and COVID Kavach ELISA antibody test results were matched in the line list, he said.

Giving a brief explanation of the survey, the Minister said that the survey revealed that 16.4% of the people were infected in the past and found to have antibodies against Covid-19 in the surveyed population. This amount is 29.1% in Delhi, 16% in Mumbai non-slum settings, 57% in slum settings, 36.1-65.4% across five prabhags in Pune, 7.8% in Indore, 22.7% in Puducherry, and 32.3% in Chennai.

The national seroprevalence survey conducted by the Indian Council of Medical Research found a seroprevalence of 0.7% in the first round (May) and 7.1% in the second round (August-September). Both rounds were conducted in 70 districts of the country. All these surveys capture only the evidence of infection in the past (IgG). The surveys done in other states were limited to capture information only within the confined limits of the metropolitan area, he said.

Compared to other studies in India, the survey undertaken in Karnataka has captured total prevalence, which includes information on both current and past infections. The participants were included from locations centred around 290 hospitals spread throughout the state of Karnataka at the district, taluk and rural areas. The survey employed all three tests: Rapid Antigen Tests, RTPCR, and antibody (IgG), said the Minister.